Derivative Financial Instruments (Notional Amounts of Derivative Contracts) (Detail) - JPY (¥) ¥ in Trillions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Derivative [Line Items] | ||
| Total | ¥ 3,236.8 | ¥ 2,483.5 |
| Interest rate contracts | ||
| Derivative [Line Items] | ||
| Total | 2,813.4 | 2,122.7 |
| Foreign exchange contracts | ||
| Derivative [Line Items] | ||
| Total | 403.7 | 346.9 |
| Equity contracts | ||
| Derivative [Line Items] | ||
| Total | 9.7 | 5.1 |
| Commodity contracts | ||
| Derivative [Line Items] | ||
| Total | 0.2 | 0.2 |
| Credit derivatives | ||
| Derivative [Line Items] | ||
| Total | 5.8 | 5.0 |
| Other | ||
| Derivative [Line Items] | ||
| Total | ¥ 4.0 | ¥ 3.6 |